Method of providing limited slip in a differential assembly

ABSTRACT

A method of providing limited slip in a differential assembly includes interconnecting an axle and a differential assembly through a first slippable linkage. The axle is driven in rotation with a first housing of the differential assembly operable to be driven in rotation by a ring gear. A plurality of pinion gears of the differential assembly are positioned in the first housing and are driven in rotation by the first housing. A side gear is fixed to the axle and is meshed with at least some of the pinion gears. The axle is operable to slip relative to the first housing. The first housing, the plurality of pinion gears and the side gear are enclosed within a second housing. The axle extends from a first end positioned within both of the first housing and the second housing to a second end positioned outside of both of the first housing and the second housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/058,588 filed Mar. 2, 2016, which is a continuation of InternationalApplication No. PCT/US2014/055114 filed Sep. 11, 2014, which claims thebenefit of U.S. Patent Application No. 61/878,685 filed on Sep. 17,2013, U.S. Patent Application No. 61/904,444 filed on Nov. 14, 2013, andU.S. Patent Application No. 62/028,583 filed on Jul. 24, 2014. Thedisclosures of the above applications are incorporated herein byreference.

FIELD

The present disclosure relates generally to differential assemblies and,more particularly, to a bolt-on configuration of a front wheel driveelectronic limited slip differential.

BACKGROUND

Differentials are provided on vehicles to permit an outer drive wheel torotate faster than an inner drive wheel during cornering as both drivewheels continue to receive power from the engine. While differentialsare useful in cornering, they can allow vehicles to lose traction, forexample, in snow or mud or other slick mediums. If either of the drivewheels loses traction, it will spin at a high rate of speed and theother wheel may not spin at all. To overcome this situation,limited-slip differentials were developed to shift power from the drivewheel that has lost traction and is spinning, to the drive wheel that isnot spinning.

A driveshaft can drive the differential through the use of a bevel gearthat meshes with a ring gear mounted to a housing or case of thedifferential. The gear arrangement can also include a pair of side gearsthat are mounted for rotation with the respective output shafts. Aseries of cross pins or pinion gear shafts are fixedly mounted to thehousing for rotation therewith. Pinion gears are individually mountedfor rotation on the pinion gear shafts and are each in a meshingrelationship with one of the side gears.

Some differential gear mechanisms include traction modifyingdifferentials. Typically, a clutch pack can be disposed between one ofthe side gears and an adjacent surface of the differential case. Theclutch pack or locking mechanism is operable to limit relative rotationbetween the gear case and the one side gear. In such differentials,engaging the clutch pack or locking mechanism (retardingdifferentiation) is achieved by one of several different approaches.Some configurations include a piston that actuates to cause the clutchpack to move between open, locked, and partially locked conditions. Insome examples it can be challenging to provide a simple arrangement todeliver hydraulic fluid to the piston without substantial modificationof existing hardware.

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named Inventors, to the extent it is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

SUMMARY

A limited slip differential assembly can include a sleeve, a supportshaft, and a clutch assembly. The sleeve can have a sleeve aperturecentered on and extending along an axis. The sleeve can also have afirst set of splines projecting inwardly from the sleeve aperture. Thesleeve can be operable to engage an axle through the first set ofsplines. The support shaft can have an outer surface, a support shaftaperture centered on and extending along the axis, and a second set ofsplines projecting from the outer surface. The support shaft can beadjacent to the sleeve along the axis and be operable to encircle andfreely rotate relative to the axle. The clutch assembly can be operableto selectively interlock the sleeve and the support shaft.

According to additional features, the limited slip differential assemblycan also include a housing defining an interior cavity containing atleast a portion of the clutch assembly. The interior cavity can beeccentric with respect to the sleeve aperture and the support shaftaperture. The clutch assembly can include a clutch basket fixed forrotation with the support shaft and at least partially encircling thesleeve. The clutch assembly can also have a clutch pack including afirst subset of plates fixed for rotation with the sleeve and a secondsubset of plates fixed for rotation with the clutch basket. The clutchassembly can also include a piston positioned adjacent to a first end ofthe clutch pack and a fluid delivery system operable to direct fluidagainst the piston whereby the piston is urged to press the clutch packagainst a portion of the clutch basket. The clutch basket and thesupport shaft can be interconnected through a third set of splinesdefined by the clutch basket and a fourth set of splines defined by thesupport shaft. The second set of splines and the fourth set of splinesof the support shaft can be spaced from one another along the axis.

A method of providing limited slip in a differential assembly caninclude interconnecting an axle and a differential assembly through afirst linkage being slippable. The method can also include coupling theaxle and the differential assembly through a second linkage beingoperable to selectively and positively lock the axle and a portion ofthe differential assembly together. The method can also includeconnecting the second linkage to the axle at a position spaced from thedifferential assembly.

According to additional features, the method can also includeincorporating a clutch assembly in the second linkage. The method canalso include positioning the first linkage within a first housing andpositioning the clutch assembly outside of the first housing. The methodcan also include positioning the clutch assembly within a second housingand linking the first housing and the second housing through a thirdhousing. The method can also include positioning the first linkagewithin a housing and projecting less than all of the second linkage intothe housing. The method can also include enclosing at least a portion ofthe second linkage in a housing and shaping the housing to be eccentricrelative to the second linkage.

According to other features, interconnecting the axle and thedifferential assembly through a first linkage can include driving theaxle in rotation with a first housing of the differential assemblyoperable to be driven in rotation by the ring gear, a plurality ofpinion gears of the differential assembly positioned in the firsthousing can be driven in rotation by the first housing, and a side gearcan be fixed to the axle and meshed with at least some of the piniongears. The axle can be operable to slip relative to the first housing.Interconnecting the axle and the differential assembly through a firstlinkage can also include enclosing the first housing, the plurality ofpinion gears, and the side gear within a second housing, wherein theaxle extends from a first end positioned within both of the firsthousing and the second housing to a second end positioned outside ofboth of the first housing and the second housing.

In other features, coupling the axle and the differential assemblythrough a second linkage can include positioning a sleeve on the axlewherein the sleeve has a sleeve aperture centered on and extending alongan axis and also has a first set of splines projecting inwardly from thesleeve aperture. The first set of splines can engage a second set ofsplines on the axle. Coupling the axle and the differential assemblythrough a second linkage can also include encircling the axle with asupport shaft wherein the support shaft includes an outer surface, asupport shaft aperture centered on and extending along the axis, and athird set of splines projecting from the outer surface. Coupling theaxle and the differential assembly through a second linkage can alsoinclude positioning a clutch assembly to selectively interlock thesleeve and the support shaft.

A method of providing limited slip in a differential assembly accordingto additional features includes interconnecting an axle and adifferential assembly through a first slippable linkage. The axle isdriven in rotation with a first housing of the differential assemblyoperable to be driven in rotation by a ring gear. A plurality of piniongears of the differential assembly are positioned in the first housingand are driven in rotation by the first housing. A side gear is fixed tothe axle and is meshed with at least some of the pinion gears. The axleis operable to slip relative to the first housing. The first housing,the plurality of pinion gears and the side gear are enclosed within asecond housing. The axle extends from a first end positioned within bothof the first housing and the second housing to a second end positionedoutside of both of the first housing and the second housing.

In other features, the axle and the differential assembly are coupledthrough a second linkage. The second linkage is connected to the axle ata position spaced from the differential assembly. A sleeve is positionedon the axle. The sleeve has a sleeve aperture centered on and extendingalong an axis and also has a first set of splines projecting inwardlyfrom the sleeve aperture. The first set of splines engage a second setof splines on the axle.

A limited slip differential assembly can include a differentialassembly, a second housing, a sleeve, a support shaft, and a clutchassembly. The differential assembly can have a first housing or case, aplurality of pinion gears, at least one side gear, and at least oneaxle. The first housing can be operable to mesh with a ring gear forconcurrent rotation. The plurality of pinion gears can be positioned inthe first housing and be driven in rotation by the first housing. The atleast one side gear can be meshed with at least some of the piniongears. The at least one axle can extend along the axis and be fixed tothe at least one side gear for concurrent rotation about the axis. Thesecond housing can enclose the first housing, the plurality of piniongears, and the side gear. The axle can extend from a first end insideboth of the first housing and the second housing to a second end spacedfrom an interior cavity of the second housing. The sleeve can have asleeve aperture centered on and extending along the axis. The sleeve canalso have a first set of splines projecting inwardly from the sleeveaperture and engaging the axle through a second set of splinesprojecting from the axle. The support shaft can project into the secondhousing and have an outer surface. The support shaft can also have asupport shaft aperture centered on and extending along the axis. Thesupport shaft can also have a third set of splines projecting from theouter surface. The support shaft can be adjacent to the sleeve along theaxis and be operable to encircle and freely rotate relative to the axle.The third set of splines can engage the first housing through a fourthset of splines projecting from the first housing. The clutch assemblycan be operable to selectively interlock the sleeve and the supportshaft.

According to additional features, the limited slip differential assemblycan also include a third housing encircling at least a portion of theclutch assembly and can be eccentric with respect to the axis. Thelimited slip differential assembly can also include a fourth housingencircling at least a portion of the support shaft and interconnectingthe second and third housings. The second housing can include a sealboss. The fourth housing can include a first portion that abuts the sealboss and a second portion that at least partially surrounds the sealboss.

According to other features, the clutch pack can include a first subsetof plates fixed for rotation with the sleeve and a second subset ofplates fixed for rotation with the support shaft. The clutch pack canalso include a piston. The clutch pack can also include a fluid deliverysystem operable to direct fluid against the piston. The piston can beurged to press the clutch pack and thereby interlock the axle and thefirst housing. The fluid delivery system can include a pump mounted in awell integrally-formed in the third housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a first front perspective view of a bolt-on electronic limitedslip differential assembly constructed in accordance with an example ofthe present disclosure and shown on a front wheel drive transaxle;

FIG. 2 is a second front perspective view of a portion of the limitedslip differential assembly shown in FIG. 1;

FIG. 3 is a magnified portion of FIG. 1;

FIG. 4 is a partial cross-section taken through section lines 4-4 inFIG. 3

FIG. 5 is a first rear perspective view of a portion of a limited slipdifferential assembly constructed in accordance with an example of thepresent disclosure;

FIG. 6 is an exploded view of the structures shown in FIG. 5;

FIG. 7 is a cross-section taken through section lines 7-7 in FIG. 5;

FIG. 8 is a front perspective view of a piston constructed in accordancewith an example of the present disclosure;

FIG. 9 is a rear perspective view of the piston shown in FIG. 8;

FIG. 10 is a cross-section taken in plane containing a central axis ofthe piston shown in FIGS. 8-9 and also containing a central axis of anorifice mounted in the piston; and

FIG. 11 is a cross-section taken through section lines 11-11 in FIG. 5.

DETAILED DESCRIPTION

A plurality of different embodiments of the present disclosure is shownin the Figures of the application. Similar features are shown in thevarious embodiments of the present disclosure. Similar features havebeen numbered with a common reference numeral and have beendifferentiated by an alphabetic suffix. Also, to enhance consistency,the structures in any particular drawing share the same alphabeticsuffix even if a particular feature is shown in less than allembodiments. Similar features can be structured similarly, operatesimilarly, and/or have the same function unless otherwise indicated bythe drawings or this specification. Furthermore, particular features ofone embodiment can replace corresponding features in another embodimentor can supplement other embodiments unless otherwise indicated by thedrawings or this specification.

With initial reference to FIGS. 1-3, an exemplary vehicle driveline isshown and generally identified with reference numeral 10. The exemplaryvehicle driveline 10 described herein is for a front wheel drive vehiclehaving a transversely mounted engine 12 (shown only as a partial engineblock in FIG. 1), although other configurations can be utilized with thepresent disclosure. The engine 12 can provide a rotary output to atransmission 14. The transmission 14 can provide a rotary output to adifferential assembly 16. The differential assembly 16 can be positionedbelow an exhaust manifold 18. The exhaust manifold 18 has been omittedfrom FIGS. 2-3. The differential assembly 16 can drive a pair of axleshafts 20 and 22 that are connected to front drive wheels (notspecifically shown).

A limited slip differential assembly 24 can include the differentialassembly 16 and a slip limiting arrangement 26. In general, the limitedslip differential assembly 24 can function as a traditional opendifferential during normal operating conditions through the differentialassembly 16. When an event occurs in which a bias torque is required,such as when a loss in traction at one of the wheels connected with theaxles 20, 22 is detected or anticipated, the slip limiting arrangement26 can be selectively actuated in order to generate the optimum biasratio for the situation.

Referring now to FIG. 4, the differential assembly 16 can include a ringgear (not shown), a first housing 30, a plurality of pinion gears 32,and at least one side gear 34. The first housing 30 can be rotatableabout an axis 36. Rotary output from the transmission 14 (referenced inFIG. 1) can be transmitted to the ring gear through the vehicle's driveshaft and a bevel gear. The first housing 30, or crank case, can bemeshed with the ring gear for concurrent rotation. The plurality ofpinion gears 32 can be positioned in the first housing 30 and can bedriven in rotation by the first housing 30. Each of the plurality ofpinion gears 32 can be mounted on posts fixed to the first housing 30.The at least one side gear 34 can be meshed with at least some of thepinion gears 32. The axle 22 can extend along the axis 36 and can befixed to the at least one side gear 34 for concurrent rotation about theaxis 36.

The limited slip differential assembly 24 can also include a secondhousing 38 enclosing the first housing 30, the plurality of pinion gears32, and the at least one side gear 34. The axle 22 can extend from afirst end 40 inside both of the first housing 30 and the second housing38 to a second end 42 (shown in FIG. 1) spaced from an interior cavityof the second housing 38.

With continuing reference to FIG. 4, the slip limiting arrangement 26can include a sleeve 44, a support shaft 46, and a clutch assembly 48.The sleeve 44 can have a sleeve aperture 50 centered on and extendingalong the axis 36. The sleeve 44 can also have a first set of splines 52projecting inwardly from the sleeve aperture 50. The first set ofsplines 52 can engage the axle 22 through a second set of splines 54projecting from the axle 22. The sleeve 44 and the axle 22 can thus befixed for rotation together.

The support shaft 46 can project into the second housing 38 and have anouter surface 56. The support shaft 46 can also have a support shaftaperture 58 centered on and extending along the axis 36. The supportshaft 46 can also have a third set of splines 60 projecting from aninner surface defining the support shaft aperture 58. The support shaft46 can be adjacent to the sleeve 44 along the axis 36 and be operable toencircle and freely rotate relative to the axle 22. The third set ofsplines 60 can engage the first housing 30 through a fourth set ofsplines 62 projecting from the first housing 30.

The clutch assembly 48 can be operable to selectively interlock thesleeve 44 and the support shaft 46. The clutch assembly 48 can include aclutch basket 64 fixed for rotation with the support shaft 46. Theclutch basket 64 can at least partially encircle the sleeve 44. Theclutch assembly 48 can also include a clutch pack 66. The clutch pack 66can include a first subset of plates 68 fixed for rotation with thesleeve 44 and a second subset of plates 70 fixed for rotation with theclutch basket 64 and the support shaft 46. The plates 68, 70 can becoated in friction material or plates of friction material can bepositioned adjacent plates 68, 70. The clutch basket 64 and the supportshaft 46 can be interconnected through a fifth set of splines 72 definedby the clutch basket 64 and a sixth set of splines 74 defined by thesupport shaft 46. The third set of splines 60 and the sixth set ofsplines 74 of the support shaft 46 are spaced from one another along theaxis 36.

A housing 76 defining an interior cavity 78 can contain at least aportion of the clutch assembly 48. The interior cavity 78 can beeccentric with respect to the sleeve aperture 50 and the support shaftaperture 58. This eccentricity is shown in FIG. 4 by the difference inthe gap between the clutch basket 64 and the inner surface of thehousing 76 between the top and bottom portions in FIG. 4.

Referring now to FIGS. 1-4, the clutch assembly 48 can also include apiston 80 and a fluid delivery system 82. The piston 80 can bepositioned adjacent to a first end of the clutch pack 66. The clutchpack 66 can be positioned between the piston 80 and a portion of theclutch basket 64. The fluid delivery system 82 can include a pump 84mounted in a well integrally-formed in a boss 86 of the housing. Thefluid delivery system 82 can be operable to direct fluid against thepiston 80 whereby the piston 80 is urged to press the clutch pack 66against the clutch basket 64. This also urges the first subset of plates68, the second subset of plates 70, and any friction plates together andinterlocks the sleeve 44 and the support shaft 46. This also interlocksthe axle 22 and the first housing 30.

The axle 22 and the differential assembly 16 can be interconnectedthrough a first linkage being slippable. The first linkage can bedefined by the first housing 30, the pinion gears 32, and the side gear34. The axle 22 and the differential assembly 16 can also be coupledthrough a second linkage being operable to selectively and positivelylock the axle 22 and a portion of the differential assembly 16 together.The second linkage can be defined by the sleeve 44, the support shaft46, and the clutch assembly 48. The second linkage can be connected tothe axle 22 at a position spaced from the differential assembly.

The first linkage can thus be positioned within the second housing 38,and the clutch assembly 48 can be positioned outside of the secondhousing 38. The clutch assembly 48 can be positioned within the housing76, and a housing 88 can link the second housing 38 and the housing 76.The second housing 38 can include a seal boss 90. The housing 88 caninclude a first portion 92 that abuts the seal boss 90 and a secondportion 94 that at least partially surrounds the seal boss 90. In theexemplary embodiment, less than all of the second linkage projects intothe second housing 38. A portion of the support shaft 46 can projectinto the second housing 38. At least a portion of the second linkage canbe enclosed in the housing 76, and the housing 76 can be shaped to beeccentric relative to the second linkage.

A second exemplary slip limiting arrangement 26 a is disclosed in FIGS.5-11. As best shown in FIG. 7, the slip limiting arrangement 26 a caninclude a sleeve 44 a, a support shaft 46 a, and a clutch assembly 48 a.The sleeve 44 a can have a sleeve aperture 50 a centered on andextending along an axis 36 a. The sleeve 44 a can also have a first setof splines 52 a projecting inwardly from the sleeve aperture 50 a. Thefirst set of splines 52 a can engage an axle 22 a (shown in FIGS. 5, 6and 11) through a second set of splines 54 a projecting from the axle 22a. The sleeve 44 a and the axle 22 a can thus be fixed for rotationtogether.

The support shaft 46 a can project into a second housing, such as secondhousing 38, and can have a support shaft aperture 58 a centered on andextending along the axis 36 a. The support shaft 46 a can also have athird set of splines 60 a projecting from the support shaft aperture 58a. The support shaft 46 a can be adjacent to the sleeve 44 a along theaxis 36 a and be operable to encircle and freely rotate relative to theaxle 22 a. The third set of splines 60 a can engage a first housing of adifferential, such as the first housing 30 of differential 16, through afourth set of splines projecting from the first housing.

The clutch assembly 48 a can be operable to selectively interlock thesleeve 44 a and the support shaft 46 a. The clutch assembly 48 a caninclude a clutch basket 64 a fixed for rotation with the support shaft46 a. The clutch basket 64 a can at least partially encircle the sleeve44 a. The clutch assembly 48 a can also include a clutch pack 66 a. Theclutch pack 66 a can include a first subset of plates 68 a fixed forrotation with the sleeve 44 a and a second subset of plates 70 a fixedfor rotation with the clutch basket 64 a and the support shaft 46 a. Theclutch basket 64 a and the support shaft 46 a can be interconnectedthrough a fifth set of splines 72 a defined by the clutch basket 64 aand a sixth set of splines 74 a defined by the support shaft 46 a.

A housing 76 a defining an interior cavity 78 a can contain at least aportion of the clutch assembly 48 a. A housing 88 a can link the housing76 a to a second housing, such as second housing 38. A mounting bracket110 a can affix the housing 76 a to a vehicle or a component of avehicle such as an engine. The interior cavity 78 a can be eccentricwith respect to the sleeve aperture 50 a and the support shaft aperture58 a. This eccentricity is shown in FIG. 11 by the difference in the gapbetween the clutch basket 64 a and the inner surface of the housing 76 abetween the left and right sides in FIG. 4.

The clutch assembly 48 a can also include a piston 80 a and a fluiddelivery system 82 a. The piston 80 a can be positioned adjacent to afirst end of the clutch pack 66 a. The clutch pack 66 a can bepositioned between the piston 80 a and a portion of the clutch basket 64a. The fluid delivery system 82 a can include a pump 84 a mounted in awell integrally-formed in a boss 86 a of the housing. The fluid deliverysystem 82 a can be operable to direct fluid against the piston 80 awhereby the piston 80 a is urged to press the clutch pack 66 a againstthe clutch basket 64 a. This also urges the first subset of plates 68 a,the second subset of plates 70 a, and any friction plates together andinterlocks the sleeve 44 a and the support shaft 46 a. This alsointerlocks the axle 22 a and a first housing.

Fluid passageways of the fluid delivery system 82 a can be definedwithin the housing 76 a. As shown in FIG. 7, a delivery passageway 96 acan extend through the housing 76 a from the pump 84 a to an outlet 98a. Fluid can be directed through the delivery passageway 96 a and out ofthe outlet 98 a by the pump 84 a. The pressurized fluid can act on thepiston 80 a. As shown in FIG. 11, a pump intake passageway 100 a canextend through the housing 76 a from an inlet 102 a to the pump 84 a.

As shown in FIGS. 8-10, the piston 80 a can include an orifice 104 a.The orifice 104 a can selectively communicate fluid between a rear face106 a of the piston 80 a and a front face 108 a. Pressurized fluid isdirected to the rear face 106 a. The orifice 104 a can be tuned suchthat when fluid pressure acting on the rear face 106 a reaches orsurpasses a predetermined level, the orifice 104 a can open to allow thepassage of fluid and reduce the fluid pressure acting on the rear face106 a.

The axle 22 a and a differential assembly can be coupled through asecond linkage being operable to selectively and positively lock theaxle 22 a and a portion of the differential assembly together. Thesecond linkage can be defined by the sleeve 44 a, the support shaft 46a, and the clutch assembly 48 a. The second linkage can be connected tothe axle 22 a at a position spaced from the differential assembly.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A method of providing limited slip in adifferential assembly comprising: interconnecting an axle and adifferential assembly through a slippable first linkage defined by theaxle and the differential assembly; coupling the axle and thedifferential assembly through a second linkage being operable toselectively and positively lock the axle and a portion of thedifferential assembly together, the second linkage including a clutchassembly having a clutch basket; connecting the second linkage to theaxle at a position spaced from the differential assembly; positioningthe first linkage within a first housing; positioning the clutchassembly within a second housing; enclosing the first housing within athird housing; and linking the second housing and the third housingthrough a fourth housing, wherein coupling the axle and the differentialassembly through the second linkage includes (i) encircling the axlewith a support shaft, wherein the support shaft includes first splinesprojecting from an outer surface that are meshed for rotation with theclutch basket, and second splines projecting from an inner surface thatare meshed with third splines projecting from an outer surface of thefirst housing and (ii) positioning a sleeve on the axle, wherein thesleeve includes fourth splines projecting from an inner surface toengage fifth splines on the axle.
 2. The method claim 1 furthercomprising: positioning the clutch assembly outside of the firsthousing.
 3. The method of claim 2 further comprising: providing thethird housing with a seal boss; and providing the fourth housing with afirst portion that abuts the seal boss and a second portion surroundsthe seal boss.
 4. The method of claim 1 wherein interconnecting the axleand the differential assembly through a first linkage further comprises:positioning the axle in driving rotation with the first housing of thedifferential assembly operable to be driven in rotation by a ring gear,positioning a plurality of pinion gears of the differential assembly inthe third first housing to be driven in rotation by the first housing,positioning a side gear fixed to the axle and meshed with at least someof the pinion gears, wherein the axle is operable to slip relative tothe first housing; and enclosing the third housing, the plurality ofpinion gears, and the side gear within the first housing, wherein theaxle extends from a first end positioned within both of the firsthousing and the first housing to a second end positioned outside of bothof the first housing and the first housing.
 5. The method of claim 4wherein coupling the axle and the differential assembly through a secondlinkage further comprises: positioning the clutch assembly toselectively interlock the sleeve and the support shaft.
 6. A method ofproviding limited slip in a differential assembly, the methodcomprising: interconnecting an axle and a differential assembly througha slippable first linkage defined by the axle and the differentialassembly, including: positioning the axle in driving rotation within afirst housing of the differential assembly operable to be driven inrotation by a ring gear, positioning a plurality of pinion gears of thedifferential assembly in the first housing to be driven in rotation bythe first housing, positioning a side gear fixed to the axle and meshedwith at least some of the pinion gears, wherein the axle is operable toslip relative to the first housing; and enclosing the first housing, theplurality of pinion gears, and the side gear within a second housing,wherein the axle extends from a first end positioned within both of thefirst housing and the second housing to a second end positioned outsideof both of the first housing and the second housing; coupling the axleand the differential assembly through a second linkage operable toselectively and positively lock the axle and a portion of thedifferential assembly together; enclosing at least a portion of thesecond linkage in a clutch housing; and coupling the second housing andthe clutch housing with a link housing extending therebetween, whereinthe second linkage includes (i) a clutch assembly disposed in the clutchhousing and including a clutch basket, and (ii) a support shaftencircling axle with a first end having inwardly extending first splinesmeshed for rotation with second splines extending outwardly from thefirst housing, and a second end with outwardly extending third splinesmeshed for rotation with fourth splines extending inwardly from theclutch basket.
 7. The method of claim 6 wherein coupling the axle andthe differential comprises: connecting the second linkage to the axle ata position spaced from the differential assembly.
 8. The method of claim6 wherein coupling the axle and the differential assembly through asecond linkage further comprises: positioning a sleeve on the axlewherein the sleeve has a sleeve aperture centered on and extending alongan axis and also has a first set of splines projecting inwardly from thesleeve aperture, wherein the first set of splines engage a second set ofsplines on the axle.
 9. The method of claim 8 wherein coupling the axleand the differential assembly through a second linkage furthercomprises: positioning the clutch assembly to selectively interlock thesleeve and the support shaft.
 10. The method of claim 9 furthercomprising: positioning the first linkage within the second housing; andprojecting less than all of the second linkage into the second housing.11. The method of claim 6 further comprising: positioning the clutchassembly outside of the first housing.
 12. The method of claim 10further comprising: providing the second housing with a seal boss; andproviding the link housing with a first portion that abuts the seal bossand a second portion that surrounds the seal boss.
 13. A method ofproviding limited slip in a differential assembly, the methodcomprising: interconnecting an axle and a differential assembly througha slippable first linkage defined by the axle and the differentialassembly; wherein interconnecting the axle and differential assemblycomprises driving the axle in rotation with a first housing of thedifferential assembly operable to be driven in rotation by a ring gear,a plurality of pinion gears of the differential assembly positioned inthe first housing and driven in rotation by the first housing, and aside gear fixed to the axle and meshed with at least some of the piniongears, wherein the axle is operable to slip relative to the firsthousing; wherein interconnecting the axle and differential assemblyfurther comprises enclosing the first housing, the plurality of piniongears, and the side gear within a second housing, wherein the axleextends from a first end positioned within both of the first housing andthe second housing to a second end positioned outside of both of thefirst housing and the second housing; coupling the axle and thedifferential assembly through a second linkage; enclosing at least aportion of the second linkage in a clutch housing; wherein coupling theaxle and the differential assembly through a second linkage comprisespositioning a sleeve on the axle wherein the sleeve has a sleeveaperture centered on and extending along an axis and also has a firstset of splines projecting inwardly from the sleeve aperture, wherein thefirst set of splines engage a second set of splines on the axle; whereincoupling the axle and the differential assembly through a second linkagefurther comprises encircling the axle with a support shaft wherein thesupport shaft includes an inner surface, a support shaft aperturecentered on and extending along the axis, first support shaft splinesprojecting from the outer surface that are meshed for rotation withclutch housing splines extending from the clutch housing, and supportshaft splines projecting from the inner surface and that are meshed forrotation with differential splines extending from the first housing;wherein coupling the axle and the differential assembly through a secondlinkage further comprises positioning a clutch assembly to selectivelyinterlock the sleeve and the support shaft; and coupling the secondhousing and the clutch housing with a link housing having a firstportion that abuts a seal boss of the second housing, and a secondportion that surrounds the seal boss of the second housing.